Doctor i saw my period on the 17th of last month and i had sex on the 27th of last month and am yet to see my period this month, could it be pregnancy?

Maybe. Maybe not.: In a woman with regular periods, some causes of a late period include: excessive weight loss or weight gain, increased exercising, emotional stress, having an illness, traveling, medicines (like birth control pills), hormonal imbalances, etc… Seeing a doctor is a good idea if symptoms are persistent, recurring, or worrisome. Pregnancy is the common cause of a missed period, if sexually active.